Delay action control switch



sPf- 28, 194.8 s. WILLIAMSON 2,450,323

DELAY ACTION CONTROL `SWITCH Filed 06f.. v3, 1944 Pire-med sept. 2s, 194s UNITED STATES PATENT OFFICE DELAY ACTION CONTROL SWITCH Stuart Williamson, Reading, England d Application October 3, 1944, Serial No. 557,036

In Great Britain September 14, 1943 4 Claims.

This invention is a delay action control device.

Its purpose is to enable a change of electrical circuit connections to be made at a predetermined interval after a control operation.

To this end the invention provides a timing device or counter which turns against the action of a re-setting spring, and is set in rotation by a control operation, such as the closing of a master switch, the timing device or counter operating electrical contacts to eiIect the desired change of circuit connections only after a predetermined extent of rotation.v

More specifically the invention is concerned with` control by effecting electrical circuit connections in apparatus which includes a constantly rotating shaft; and a further object of the invention is to utilise such constantly rotating shaft for driving the timing device.

To this end the invention provides a control device for use in connection with apparatus including a rotating shaft in which an initiating control operation, such as the closing of a master switch, establishes a driving connection between the rotating shaft and the timing device, the timing device being thereby rotated until it effects the desired change of circuit connections after a predetermined amount of turning.

A further object of the invention is to make it possible to Vary at will the length of the interval which elapses between operation of a master control and the consequent change of circuit connections. To this end the invention provides stationary and moving co-cperating abutments, the latter upon the rotating timing device, and one of them adjustable, which abut one upon the other and thereby limit the movement of the timing device under its re-setting spring. A further and particular object of the invention is a delay action control device of very simple construction capable of adaptation to any apparatus which includes a constantly rotating shaft and suited for electrical actuation from a distance. Such control device includes a relay the circuit of which is governed by a master switch, and the amature of which effects the desired change of circuit connections by operating contacts, and also includes a timing device having as one element a disc with a notched periphery mounted for rotation upon the relay armature in proximity to the constantly rotating shaft of the apparatus. ARetraction of the relay armature brings the periphery ofv the disc ,into frictional contact with the rotating shaft before the armature has moved far enough to eiect a change of circuit connections, and the timing device is then driven by the shaft until the (Cl. F-375) 2 notch in the periphery of the disc registers with the shaft, whereupon the armature is further re# tracted and the change of circuit connections is effected. 6 By way of illustration of the many purposes and kinds of apparatus to which the delay actiony control device of the invention may be applied may be mentioned the instance of an electrically driven camera associated with a tire-arm vfor relO. cording the effect of nre Vfrom the weapon; it must be clearly understood that the invention is not limited to this illustrative application. It is common to cause such'a recording camera to start when the trigger of the weapon is pressed v and to stop when the trigger is released. `Bui; to

shouldcontinue 4,running after the trigger is released until the 'last projectile has reached its target, For this the delay action control device ,20, of the invention readily provides. The master control operation of releasing the trigger, instead of stopping the camera, sets the timing device in operation, and the camera is switched oil' only when the timing device' has performed a Dre.- determined extent of travel. For economy of nlm, which is especially important when the recording camera is carried on an airplane, it is desirable to make the length of over-run of the camera be yond the instant of release of the trigger correspond to the muzzle velocity and effective range of the particular weapon with which the camera is associated; this, therefore, is an instance where the delay action control device may conveniently be fitted with means for varying the extent of the delay.

The fdelay action control device is capable of embodiment in many diirerent forms. By way of illustration two forms are shown in the accom`- panyi'ng drawings. The invention is not to bere- 40 garded as' limited to these particular constructions; the scope of the invention is to be gathered from the appended claims.

Figure 1 shows diagrammatically a construction of the invention for use in any apparatus which includes a constantly rotating shaft.

Figure 2 is an end elevation in section on the linel II--II of Figure 3.

Figure -3 is a side elevation and .Figure 4 a plan in section on the line IV--IV of Figure 3 of a construction of the invention partic-y ularly intended for recording cameras used with. weapons.

Figuie 1 shows an electric motor I supplied from-a source'represented by main conductors l. As indicated by the mechanical connection A -3 'f obtain a fullrecord of the effect oi fire the camera shown in dotted lines the motor drives an apparatus, for example a kinematograph camera. which being no part of the invention is not shown. The

Vfree end it carries a yieldingly mounted contact II, which when the relay is excited, abuts upon a fixed contact I2. The contacts Ii and I2 are included in the supply circuit of the motor I, which therefore is interrupted by their separation.

Upon an extension I3 beyond its pivot the armature 8 carries a rotatable disc I4. A spiral spring I5 anchored at one end to the disc I4 and at the other end to the armature I2, resists rotation of the disc and returns the disc to a zero position when it is otherwise unrestrained. In the periphery of the disc I4 is a semicircular notch i6 of slightly greater diameter than the shaft 4. The disc I4 carries on its face a projecting pin I1 in the path of which is a xed but preferably adjustable abutment I8. As shown the abutment I8 is adjustable along the fixed arcuate slotted support I9 which is substantially concentric with the disc I4, and the abutment may be clamped in any position to which it is adjusted by the screw I0.

When the camera is not in action the circuit of the relay I is interrupted by the switch 0, the relay armature is not attracted. and the disc I4 is in the position indicated, save that the spring holds the notch I8 in its periphery in engagement with the shaft 4; the shaft 4, the motor I and the camera are all at a standstill.

Upon the gunner pressing the trigger of the weapon with which the camera is associated the switch 4 is closed. The relay 1 is therefore excited, and attracts its armature 8, withdrawing the disc I4 from engagement with the shaft 4, and bringing the contacts I I, I2 together; the circuit of the motor I being thus closed the motor'starts, and drives the camera and the gear wheel and shaft 4 at a steady speed. The disc I4, being freed, is turned by its spring I5 until its projection I1 encounters the abutment I2.

When the trigger of the weapon is released the switch 0 is opened and the circuit of the relay is broken. The relay therefore releases its armature 8 and the armature is retracted by the spring 2 until the periphery of the disc I4 is brought into firm frictional contact with the now rotating shaft 4; this amount of retraction of the armature does not separate the contacts II, I2. A driving connection is thus established between the driven apparatus, the camera, and the-timing device or counter which is the disc I4 and the parts associated with it. The disc is rotated against the action of its spring II, which is thereby wound up; and it continues rotating until the notch I0 is brought into register with the shaft 4, whereupon the spring 9 further retracts the armature l, engaging notch Il with the shaft 4 and separating the contacts II, I2. The circuit of the motor is thus broken and the apparatus comes to a standstill, friction of the notch Il with the shaft 4 contributing, if desired, to its arrest.

The separation of the contacts I I, I2 takes place when the disc I4 has rotated an extent predetermined by the position of the abutment I8, after release of the relay has established the aforesaid driving connection. The number of succes4 sive operations of the camera will depend on this predetermined extentA of rotation of .the disc I4 and the gear ratio of the driving connection between the camera and the disc;'in effect the disc counts the revolutions of the shaft 4 and after a predetermined number causes the contacts II, I2 to separate.

In the construction of Figures 2 to 4 the constantly rotating shaft, not shown, of a kinematograph camera drives a gear wheel 2l meshing with a pinion 22; an eccentric pin 22 in the pinion 22 engages in a slot 24 in a pivoted arm 2l carrying the nlm feed pawl 24 of the camera. This mechanism is well known and forms no part of the present invention; it is shown because the drive of the timing device is taken from it. The timing device or counter comprses a ratchet wheel 21, which is under the control of a spiral spring 2l tending to turn the wheel clockwise in Figure 3. The wheel 21 can be turned .against the action of its spring 22 by a pawl 2l carried upon a rocking arm 2| which rests upon and is rocked by the arm 25; a spring 3l both keeps the arm 32 in contact with arm 2l and tends to engage the pawl 2| with the ratchet wheel 21. A detent 22 carried .by the amature 22 of a relay 34 normally retains the wheel 21 when wound against the action of its spring 2l by the pawl 2l. The motor which drives the camera has in its circuit the contacts 2l, 24, which normally rest in abutment but can be separated by rocking lever 21 the nose 2l of which engages one of the contacts, while the tail of the lever lies in the path of a pin 22 upon the ratchet wheel 21. A spring retracts the armature 22 i. e. swings it clockwise in Fig. 3 when the relay 2E is not excited.

As in the construction of Figure 1 the relay 24 is controlled by a master switch, not shown, which completes its circuit when fire is opened and breaks its circuit when the trigger of the weapon is released. The extent of delay in stopping the camera after the master switch is opened is determined by an abutment 4I upon a disc 42, this abutment extending into the path of a second pin 42 upon the ratchet wheel 21. The disc 42 canbe turned by inserting n. screwdriver in the slot of a head 44 upon the stem of which the disc is mounted, and the disc is frictionally held where set 'by dished spring 4l. 1

When the master switch is closed the 'relay 24 attracts its amature 2l. and lifts the detent 22 out of engagement with the ratchet4 wheel 21.

Also the tail of the amature engages the end of 66 the pawl 2l, and lifts that also out of engagement with the ratchet wheel. Consequently the ratchet wheel is free to turn under the action of its spring 22, and rotates clockwise in Figure 3 until its pin 42 encounters the abutment 4I. The ratchet wheel 21 is idle so long as the relay 24 is excited. The pawl 2l is rocked idly to and fro out of engagement with the ratchet wheel 21. When the trigger is released the amature 22 is retracted by its spring 44 and both the detent 22 and the pawl 29 re-engage the ratchet wheel. Consequently the ratchet wheel 21 is now rotated against the action of its spring 2l, until its pin lencounters the end of the lever 21 and moves the lever over, to the left in Figure 3, causing it to separate the contacts Il, 2l, so interrupting the circuit of the camera motor and bringing the camera to rest.

This rotation of the ratchet wheel 21 takes place tooth by tooth, one tooth for each revolution of the wheel 22. Thus the wheel 21 in effect counts the revolution of the wheel 22 and therefore the cycles of operation of the camera, and after an extent of rotation determined by the position of the abutment 4| and the number of teeth on the wheel 21 between that position and the position of the pin 39, causes the contacts 35, 3B to be separated.

I claim:

1. A delay action control device for apparatus which includes a constantly rotating shaft comprising in combination with said shaft a master switch, a relay, an exciting circuit for said relay controlled by said master switch, an armature rocked by said relay, a timing device including a disc mounted for rotation upon said armature in such proximity to said shaft that the periphery of said disc is brought into frictional contact with said shaft upon retraction of said armature, a spring wound by the rotation of said disc, and electrical contacts oper-ated by said timing device after a predetermined extent of rotation of said disc.

2. A delay action control device for apparatus which includes a constantly rotating shaft comprising in combination with said shaft a master switch, a relay, an exciting circuit for said relay controlled rby said master switch, an armature rocked by `said relay, a timing device including a disc with a notched periphery mounted for rotation upon said armature in such proximity to said shaft that the periphery of said disc is brought into frictional contact with said shaft upon retraction of said armature, a spring wound by the rotation of said disc, and electrical contacts operated by said timing device when the notch in the periphery of said disc registers with the shaft.

3. A delay action control device for apparatus which includes a constantly rotating shaft comprising in combination with said shaft a master switch, a relay controlled by said master switch. an armature rocked by said relay, a fixed contact,

a moving contact mounted on saidv armature,

a timing device including a disc with a notched periphery mounted for rotation upon said armature in such proximity to said shaft that the 5 periphery of said disc is brought into frictional contact with said shaft upon the retraction of said armature before the fixed and moving contacts are separated by such retraction, "the registering of the notch in the periphery of the disc with said shaft permitting suflicient further retraction of said armature to separate said contacts.

4. A delay action control device for apparatus which includes a constantly rotating shaft comprising in combination with said shaft a master switch, a relay, an exciting circuit for said relay controlled by said master switch, an armature rocked by said relay, a timing device including a disc mounted for rotation upon said armature in such proximity to said shaft that the periphery of said disc is brought into frictional contact with said shaft upon retraction of said armature, a spring wound by rotation of said disc as a result of such frictional contact, co-operating members one of them upon said disc positioned to abut and thereby limit,the rotation of said disc by said spring, one of said co-operating members being adjustable, and .electrical contacts operated by said timing device after a predetermined extent of rotation of said disc.

STUART WILLIAMSON.

REFERENCES CITED The following references are of record in the 35 ille of this patent:

UNITED STATES PATENTS Number Name Date 1,603,049 Hall Oct. 12, 1926 2,342,509 Gaty et al. Q--- Feb. 22, 1944 2,342,510 Fischer et al. Feb. 22, 1944 

